The operation life of rechargeable battery cells is significantly depending on the temperature of the battery cells during their operation life. In order to obtain a longest possible operation life for battery cells their operating temperature should be maintained on a certain level or within a certain temperature range during operation. Recharging or discharging battery cells creates thermal energy which has to be conducted from the cells as effectively as possible. Further, in some situations it must be possible to warm up the battery cells in order to get them to a desired operating temperature. Also, during charging or discharging of a battery, internal resistances of the battery terminals form waste energy which transforms to heat. This heat should also be conducted away. So, the most effective way of cooling would be cooling directly from the battery terminals. However, a great short-circuit risk causes a big challenge for this type of cooling.
The battery cells should also be protected against damages and deformation. When being damaged the battery cells may form short-circuit which could lead to an uncontrolled electric discharge in a form of a fire or an explosion. If possible, the deformation of battery cells should be prevented by a safe structure which takes various accident situations into account.
One example of prior art systems is disclosed in publication US 2012/0148881 A1. This publication discloses a battery-cooling system including a battery array and a plurality of heat pipes. The heat pipes each include a low-profile extrusion having a plurality of hollow tubes formed therein. Each heat pipe includes an evaporator portion and a condenser portion. A heat-transfer fluid is disposed within the plurality of hollow tubes. The evaporator portion is disposed between successive batteries within the battery array. The condenser portion is disposed outside of the battery array and exposed to as heat sink. The structure shown in this publication does not form any support structure, housing or supporting frame for the battery cells and battery modules comprising a plurality of battery cells.
A further prior art system is disclosed in publication US 2009/0180251 A1. This publication discloses a housing made of aluminum alloy extruded section member for manufacturing waterproof power electronic devices. The extruded section forms a tunnel that is substantially rectangular and is provided with fins on at least one side of the rectangle. The fins allow air to flow outside the housing by natural convection in the extrusion directions. A side without fins serves as a base for fastening the housing and as a support for power electronic components of the power electronic device. The fins are machined transversely to the extrusion direction to form notches in the fins. The notches are aligned in succession to allow air to flow outside the housing by natural convection in the optimum direction. This publication is silent about any battery cells, but if the housing disclosed in this publication were used to locate battery cells inside it, said battery cells could not be positioned so that good thermal conductivity could be achieved.